Getting a Better Understanding of Windows 7 Libraries

When you work with libraries, it is important to remember that they are only representations of collected data. Windows 7 creates merged views of files and folders that you add to libraries. As the libraries themselves do not contain any actual data, any action you take on a file or folder within a library is performed on the source file or folder. You can create new libraries to act as views to various collections of data as needed by right-clicking the Libraries node in Windows Explorer, pointing to New and then selecting Library.

If you’re ever curious about how libraries really work, access the %HomeDrive%\
%HomePath%\AppData\Roaming\Micrdosoft\Windows\Libraries folder. In this folder, you’ll find the library definition files for your user profile. Each library definition file ends with the .library-ms extension and is formatted as an XML file that follows Microsoft’s Library naming schema. If you view a library definition file, you’ll find that it uses simple locations to define where contents in the library originate from. Folder and files are referenced by globally unique identifiers (GUIDs) and the serialized contents of a particular location are encrypted. Some properties of libraries are tracked in the registry, but these are primarily used only when you want to restore the original libraries, which you can do in Windows Explorer by right-clicking the Libraries node and selecting Restore Default Libraries.

Note also that the %Public%\Libraries folder also may have library definition files. For example, Windows Media Player and Windows Media Center both make use of the Recorded-TV library. As this library isn’t a standard library in your user profile, it is represented in the %Public%\Libraries folder by the Recorded-TV.library-ms file.

Source of Information : OReilly Windows 7 The Definitive Guide